Question

What is a repetition structure?

Short answer

Provide an example to illustrate the concept. Answer: A repetition structure, or loop, is a sequence of instructions in programming that is executed repeatedly based on specific conditions. There are two main types of loops: for loop and while loop. Loops contain three essential parts - initialization, condition, and update. They can be used to solve problems that require repetitive actions, such as calculating the sum of the first 10 natural numbers. For example, using a for loop, the sum of the first 10 natural numbers can be computed by initializing a sum variable to 0, creating a loop that iterates 10 times, adding the current loop variable value to the sum variable in each iteration, and after the loop, the sum variable will contain the desired result.

Step-by-step solution

Definition and Examples

A repetition structure (also called a loop) is a sequence of instructions in computer programming that is executed repeatedly, based on specified conditions. There are two main types of loops: for loop and while loop. For example, let's say you want to print the numbers from 1 to 5 using a loop, it would look like this: For Loop (C++): ``` for (int i = 1; i <= 5; i++) { cout << i << endl; } ``` While Loop (Python): ``` i = 1 while i <= 5: print(i) i += 1 ```

Parts of a Loop

In a loop, there are three essential parts: 1. Initialization: Setting the starting value of the loop variable. For example, in both examples above, we set the value of 'i' to 1. 2. Condition: The loop will continue executing while this condition holds true. In both examples, our condition is "i <= 5". 3. Update: Modifying the loop variable after each iteration. In both examples, the loop variable 'i' is incremented by 1 ('i++' in C++, 'i += 1' in Python) after each iteration.

Using a Repetition Structure to Solve a Problem

Let's see an example. Suppose that you are given a task to find the sum of the first 10 natural numbers. You can use a loop to solve this problem as follows: 1. Initialize the sum variable to 0. 2. Use a loop that iterates 10 times. 3. In each iteration, add the current value of the loop variable (i) to the sum variable. 4. After the loop, the sum variable will have the desired result. Example (using a for loop in C++): ```cpp #include using namespace std; int main() { int sum = 0; for (int i = 1; i <= 10; i++) { sum += i; } cout << "The sum of the first 10 natural numbers is: " << sum << endl; return 0; } ``` In this example, we have found the sum of the first 10 natural numbers using a for loop as our repetition structure.